Carbon Capture and Sequestration (CCS) is the process by which carbon dioxide is captured from coal fired power plants and stored in either underground, offshore (below the ocean bed) or in mineral deposits, thus preventing it from being released into the air. The process involves three stages: (1) capture of CO2 at point sources (such as power plants) and compression of the gas, (2) transportation through pipelines and (3) sequestration (geological, marine, or mineral). Although long-term costs associated with CCS may be cost-competitive (as indicated in the chart it Part 2), within each part of the process, different technologies exist with varying costs based on their level of development and maturity, elaborated below. CCS is an emerging technology which has still uncertain costs. While feasibility studies and pilot projects have been undertaken, large-scale commercial demonstration projects have not yet been carried out, although some are in planning stages. Cost uncertainty also exists around site-specific variability.